1. Field of the Invention
The present invention relates to packaging and a method of storing a detachable and exchangeable ink jet printing head which is to be mounted on an ink jet printing device.
2. Description of the Prior Art
An ink jet printing device is a device designed to print out characters and other marks on a paper or on other recording media by ejecting liquid ink from a printing head. The types of the printing head primarily include a permanent type, in which the printing head is permanently fixed to the printing device, and a detachable type, in which the printing head is easily detachable for exchange by users.
As for the permanent type printing head, an ink jet printing head is already mounted on the printing device upon the shipment of the printing device. Therefore, the user of the printing device is exempted from exchanging the printing head except in the case of a printing head malfunction, upon which sufficiently good printing is hindered, then the exchange of the printing head by calling a serviceman becomes inevitable.
For the permanent type printing head, normally, printing ink or preservation liquid is filled in the printing head and a cap is applied on the outlet of the printing head for transportation and storage in order to prevent the leakage of the ink.
On the other hand, as to the detachable type printing head, a printing head and an ink reservoir are integrally constructed, where the integral printing head and the ink reservoir are easily detachable when the ink is exhausted, or each of the printing head and the ink reservoir can be separately detachable by the user.
As for the detachable ones in the case of the former, in which the printing head and the ink reservoir are integral, then, for instance, as disclosed in Japanese laid-open Patent Publication No. 60-204366, the internal pressure of the containing package is reduced and the meniscus of ink located at the nozzle is moved to the inside of the reservoir in order to eliminate the disadvantage of ink leakage or ink adhesion caused by evaporation of ink from the nozzle upon transportation and storage.
Also, regarding the latter of the detachable type printing head mentioned above, each of the printing head and the ink reservoir is separately packaged. In this case, ink or a sort of liquid called "clear ink" which is the liquid content excluding ink coloring ingredients, is charged and then sealed or capped to prevent the leakage of ink from the printing head nozzle. As mentioned above, the detachable type printing head charged with ink or clear ink brings about the evaporation of charged ink with the elapse of time when they are stored. When evaporated, it brings about the adhesion of ink coloring ingredients on the ink discharge driving element such as an electro-thermal conversion unit. In order to avoid such a problem, as disclosed in Japanese laid-open Patent Publication No. 61-25844, the package itself is charged and saturated with the same substance as that of the ink evaporation component, or as disclosed in Japanese laid-open utility model Publication No. 61-93264, the package itself is made of a material having a low gas permeability.
However, it is extremely difficult to prevent ink evaporation completely and it is also extremely difficult to actually avoid the adhesion of the ink coloring ingredient at the inside of the printing nozzle. As it is uncertain to conduct good printing immediately after the installation of a printing head with adhered ink coloring ingredients at the inside of the nozzle, normally, a certain recovery operation is conducted in order to recover the ink discharge condition. This recovery operation inevitably require much consumption of ink to meet the requirement for a satisfactory level of recovery for a most deteriorated nozzle discharge.
Also, on the printing head, some electrodes are provided to receive signals from the printing device, and the evaporation of ink within the package causes oxidation on the electrode surface which results in an undesirable situation.
As mentioned already, the sealing materials such as seals, caps and the like provided on the discharging portion of the printing head, have to be removed by the users for mounting on the printing device and, upon such removal, it is very likely to stain the user's fingers with the ink which comes out from the printing head and is scattered therefrom.